The present invention relates to a method and apparatus for sensing the position of a hub filler of a tape drive between a single reel tape cartridge and a take-up reel.
Single reel tape cartridges are used to transport and store tape for reel-to-reel tape drives. A single reel tape cartridge is inserted into a tape drive and a mechanism is used to load the end of the tape into a take-up reel from the tape cartridge. Once the end of the tape is loaded into the take-up reel, the tape drive operates as a reel-to-reel tape drive. A motor is coupled to the take-up reel to rotate the take-up reel about the take-up reel axis and another motor is coupled to the single reel tape cartridge to rotate the reel of the tape cartridge about its axis.
The tape drive loading mechanism attaches to a tape leader pin. The tape leader pin is located at the end of the tape which is contained in the single reel tape cartridge. A slot in the hub filler is used for receiving the tape leader pin. The hub filler is driven by a guide arm between the single reel tape cartridge and the take-up reel. An example of a mechanism for driving the hub filler between the tape cartridge and the take-up reel is disclosed in U.S. Pat. No. 6,034,839.
FIG. 1 is a view of the tape drive loading mechanism disclosed in U.S. Pat. No. 6,034,839. The hub filler 300 enters into the cartridge 210 and attaches to the end of the tape. The hub filler 300 then moves along a guide rail 247, driven by the guide arm 250. Typically, the hub filler 300 attaches to the end of a tape in the tape cartridge 210 and the guide arm 250 moves the hub filler 300 along the guide rail 247, trailing the tape across the read/write head 222 and into the take-up reel 242. The hub filler 300 enters the take-up reel 242 through a channel 244 and into the hub 245 of the take-up reel 242.
FIG. 2 is a top view of the tape drive, depicting the hub filler 300 in the take-up reel 242 with the tape 216 attached. The tape 216 passes across the read/write head 222 and the end of the tape 216 is secured to the take-up reel 242. The tape drive is then operated by rotation of the take-up reel 242 and the single reel of the cartridge 210 about their respective axes to move the tape 216 across the read/write head 222. Motors are used to rotate the take-up reel 242 and the single reel of the cartridge 210, controlling the speed of the tape 216 as it moves across the read/write head 222. The hub filler 300 pivots on an axle 252 that is coupled to the guide arm 250. This pivoting is necessary for the hub filler 300 to be guided on the guide rail 247 into the take-up reel 242. Once the hub filler 300 is in the take-up reel 242, with the tape 216 attached, the take-up reel 242 rotates to thereby unload the tape from the cartridge 210. The hub filler 300 rotates with the take-up reel 242 on the axle 252. The loading mechanism attempts to align the axle 252 axis and the take-up reel 242 axis perfectly.
There are some concerns regarding the tape drive loading mechanism described above. Perfectly aligning the hub filler""s axle axis and the take-up reel axis is very difficult to do, due to mechanical tolerances. Misalignment can cause minor imbalances during rotation of the take-up reel; these minor imbalances can create small speed variations in the tape wind and unwind speeds. These variations in speed are difficult for the motors of the take-up reel and cartridge reel to compensate for. Hence, the variations in speed deter from the quality of the reading and writing of the tape at the read/write head. Additionally, misalignment of the hub filler axis and the take-up reel axis reduce the life of the bearings in the take-up reel. Worn bearings will produce vibrations and result in noise during recording and reading at the read/write head.
Controlling the hub filler at the single reel tape cartridge to attach to a tape leader pin is somewhat difficult to consistently accomplish. This difficulty arises from the circumstance that the tape leader pin is very small and the slot in the hub filler for receiving the tape leader pin is very small. Small misalignments or miscalibrations of the movement of the hub filler at the single reel tape cartridge may cause a failure of the hub filler to pick up the tape leader pin and thereafter load the tape from the tape cartridge onto the take-up reel. Hence, misalignment of the hub filler at the single reel cartridge can cause a malfunction in the tape drive loading mechanism and therefore make the tape drive loading mechanism unreliable.
There is a need for a tape drive loading mechanism with the ability to sense the precise position of the hub filler during loading and unloading of tape from a removable tape cartridge.
These and other needs are met by embodiments of the present invention, which provide sensors for sensing the precise position of a guide arm. More specifically, the present invention relates to an apparatus for loading a take-up reel with tape from a removable tape cartridge. The apparatus comprises a hub filler for transporting an end of the tape from the tape cartridge to the take-up reel. The hub filler is driven by a guide arm along a guide rail from the removable tape cartridge into the take-up reel. The apparatus also comprises at least one sensor for detecting the position of the hub filler. The tape loading mechanism of the present invention uses feedback from the at least one sensor to control the motor that drives the guide arm that drives the hub filler. The present invention has the advantage of utilizing the feedback from at least one of the sensors in a precise manner to detect and utilize the exact position of the hub filler to reliably attach and detach the hub filler to the tape leader pin at the removable tape cartridge and to precisely align the axle of the hub filler in the take-up reel. The present invention also eliminates the need for the tape loading device to rely on encoded motor positions, which can be miscalibrated, to position the hub filler.
There are several advantages of the present invention. The present invention enables the hub filler axis and the take-up reel axis to be precisely aligned as the hub filler attaches to the take-up reel. The present invention mitigates imbalances during rotation of the take-up reel. These imbalances create small speed variations in the tape wind and unwind speeds as a result of the misalignment of the hub filler axis and the take-up reel axis. Another related advantage of the present invention is that the bearings are not damaged due to the misalignment of the hub filler axis and the take-up reel axis. Worn bearings produce vibrations that cause noise in the read/write head during reading and writing of the tape. Yet another advantage of the present invention is that the hub filler can attach to the leader pin consistently and reliably, as the position of the hub filler and the timing of the gearing mechanisms can act cooperatively to efficiently and effectively enable the attachment of the leader pin to the hub filler. The above-listed advantages are examples and not exclusive.
The foregoing and other features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the present invention, taken in conjunction with the accompanying drawings.